I know that feeling well. There isn't a wonder cure, but try taking a hot shower and then writing or making graphics, or just reading some dramatic fic from a writer who has made you feel plucky or triumphant or cackly in the past, to get some endorphins going without exerting yourself, and intersperse it with some small chore, like switching or folding laundry or changing pillowcases or straightening a small area--sometimes feeling clean, kicky, and just a little bit productive helps. And seriously, keep pushing the clear fluids (and no, vodka does not count ;) ) and don't get too warm apart from a shower--you don't want to get chilled, but cold doesn't make people sick; it's holing up in warm enclosed places during cold weather that provides a breeding ground for germs. If you do have a bug of some sort, you don't want to foster it.